1. Field of the Invention
The present invention relates to water cooling of an electronic apparatus and more particularly, the present invention relates to an apparatus and a method for cooling electronics, a coolant shielded electronic apparatus, and a method for cooling electronics.
2. Description of the Related Art
An electronic apparatus including such as a personal computer, a server, a workstation and/or a mainframe computer typically requires a cooling device for cooling a heat source such as a microprocessor unit (hereafter referred to MPU) or a central processing unit (hereafter referred to CPU) to maintain stable performance thereof. In nowadays, operations of the electronic apparatuses in a high performance and a high clock rate are increasingly requested yet and then, the heat generation from the electronic apparatuses rises an old but yet new problem in the computing technology.
The problem is the heat generation of the MPU and/or the CPU and there is a technical prediction that a density of the heat generation of a recent MPU with which the operation clock rate is at about several Giga-Hertz goes over that of an atomic reactor and should reach to the heat generation density of sun in near future.
One strategy to reduce the heat generation problem is to make the MPU and/or the CPU in multi-core architectures so as to reduce instructions per a single core while maintaining an overall performance; however, as the clock rate for the single core goes higher and higher with respect to performance improvements, the trade-off problem between the heat exhaust and processor performance will make a high barrier for the recent processor technology.
Furthermore, recent electronic apparatuses tend to employ a number of the MPUs and/or the CPUs which are operated cooperatively with each other, i.e., so called GRID Computing as well as the multi-core architecture as described above so that an information processing density per an electronic apparatus also increases even if the clock rates for unit MPU and/or CPU is suppressed; this tendency will be further accelerated as the multi-core architecture or the grid-computing between processors becomes more and more popular and as high performance operations for the electronic apparatus are requested.
From the above computing environment, in a data center handling huge amounts of information such as Internet data, information for a search engine, or enterprise data, a number of computing facilities are placed and are operated in the mutual cooperation thereof. Such data center tends to develop the computing performance thereof for addressing to increasing demands for high performance computations so that heat management of the data center becomes a serious problem to be settled urgently in relation to global warming due to the computation as well as reduction of investment costs for the data center.
As another strategy for settling to the heat exhaust from the MPU or the CPU in the electronic apparatus, a direct cooling architecture for the MPU and/or the CPU by an adequate coolant is known.
FIG. 14 shows a typical cooling system 1400 for the electronic apparatus employing an air-cooling mechanism. The cooling system 1400 of FIG. 14 is constructed for cooling the electronic apparatuses while conducting air-conditioning in a computing room. In the space of the computing room, the electronic apparatuses 1440 are placed on the floor 1410 to computing various data. The electronic apparatus 1440 may be, for example, workstations, servers and/or mainframe computers etc.
The chiller units 1420 are placed in the computing room so as to supply chilled air primarily to the space 1450 created under the floor 1410. The space 1450 provides a fluid path for the chilled air etc. The floor 1410 comprises a plurality of perforated panels through which the chilled air can pass upwardly from the space 1450 to the computing room.
Positions of the perforated panels 1430 at the floor 1410 are determined depending on positions of chilled air inlets of the electronic apparatus 1440. The chilled air is supplied into the spaces provided between the electronic apparatus of which air-intake sides, i.e., the cold sides thereof are facing each other.
Referring to FIG. 15, schematic air flows of the cooling apparatus 1500 in FIG. 15 are illustrated. The chilled air 1570 passes the under-floor space 1595 and flows into the computer room from the under floor space 1595 at the position of the perforated panels 1580. The perforated panels 1580 are disposed between the electronic apparatuses positioned to face the cold sides thereof each other.
The chilled air is then drawn into both of the electronic apparatuses from the cold side and conducts the heat exchange with the MPUs and/or the CPUs assembled in the electronic apparatus. Then, the heated air 1590 is discharged from hot sides of both of the electronic apparatuses. Thereafter, the discharged heated air 1590 flows upwardly and then flows laterally toward the CRACs, i.e., Computing Room Air Conditioners 1510, 1560 so as to regenerate the chilled air by air conditioning members within the CRACs 1510, 1560. Then, the chilled air 1570 is again supplied to the under-floor space 1595 for the heat management of the electronic apparatus.
In the described conventional cooling apparatus, the chilled air is mainly used for cooling the MPU and/or the CPU; that is to say, most of the chilled air is consumed for cooling of the electronic apparatus. Then, the air-conditioning in the computing room must be prepared as a separate air conditioning system. Alternatively, the cooling capacity of the CRACs must be increased for settling the entire air conditioning in the computing room.
Direct cooling architecture for the electronic apparatuses have been developed so far for addressing to heat removal of the information processing apparatus. For example, Japanese Patent (Laid-Open) No. 2002-374086 discloses a cooling apparatus for a rack-mounted information processing apparatus. In the scheme disclosed therein, the rack including a water cooling unit is employed and water flow paths are provided in each of columns of a rack cabinet. The water passed through the column is then introduced to the rack and a water cooled jacket for CPU/LSI so as to cool elements within the rack.
Japanese Patent (Laid-Open) No. 2005-100091 also discloses a cooling module disposed directly on the CPU for sharing a water cooling module and a forced air cooling module such that both of the air and water cooling architectures may be switched.
Japanese Patent (Laid-Open) No. 2006-285670 also discloses a blade for information processing and an information processing apparatus including the blade. The disclosed blade is cooled by the water passing through water paths provided in the blade. The CPU or other heat sources are placed on the blade in heat exchange relation to the blade and hence, the heat sources are cooled by the water cooled blade.
As described above, the water cooling architecture is regarded as suitable for the cooling architecture of the electronic apparatus; however, it is known that water has potential defects for causing an electronic leak when the water immerses into the electronic apparatus. When the water is leaked in the enclosure of the electronic apparatus, the electric apparatus or facilities such as a data center would suffer huge and high cost damages.
In order to settle to the leak of the water, many attempts have been made so far. For example, Unexamined (Laid-Open) Japanese Publication No. 3191274 (also published as Japanese Patent (Examined) Publication No. 7-117330), discloses a cooling apparatus which comprises, in a recycle path of a liquid cooling media, a removal apparatus for corrosive ions. The removal apparatus disclosed may remove selectively anions acting corrosive factors to improve the corrosion of the cooling apparatus.
Although attempts for improving hazardous water leak from the cooling system of the electronic apparatus have been made, corrosion mechanisms of lines etc. are not yet understood sufficiently. Thus, the protection from the problems caused by the corrosion under various conditions is not yet practically ensured, because the corrosions and their magnitudes substantially depend on particular environments in which the electronic apparatuses are placed.
In addition, factors for causing the water leak may include, other than the corrosion, for example, cracks or damages by impacts as well as loosed joint connections such that it is difficult to settle the above various factors and to overcome the adverse effects when all of the above factors are considered.
Consequently, an effective cooling apparatus is yet requested and the needs thereof becomes larger and larger as the high performance computing paradigm becomes realized by advances of device and information technologies while providing the heat management of the data center. Further yet there are increasing needs for overcoming the heat exhaust of the electronic apparatuses and thence, a novel cooling apparatus for electronic apparatus including the MPU and/or the CPU has still been expected.